With 43 young Mexicans still missing, the country's illustrators are using art to call for answers.

On 26 September, a coach of male students from Ayotzinapa teacher training college in southern Mexico were on their way to protest over school hiring practices. They were stopped by police who shot at their buses; three were killed. But there is a mystery around 43 others, who have not been heard from since - with speculation police may have handed them over to local militia or a drug cartel.

Image copyrightTumblrImage caption
Valeria Gallo's portrait

The story has moved the Mexican public, with protest marches by thousands, desperate to know the truth. Now, more than 200 artists from across the country have added their voices, and their talents, to those calling for answers. Using the hashtag #IlustradoresConAyotzinapa (#IllustratorsForAyotzinapa), they are painting portraits of the missing individuals. Many of these images are going viral, and the hashtag has now been used over 14,000 times.

Image copyrightTumblrImage caption
Bef's portrait

Valeria Gallo is one of those artists disillusioned by her government's handling of the incident. She has a son, and told BBC Trending she does not want him growing up in a Mexico where kidnappings and murder are accepted by society. At random she chose one of the missing students, Benjamin Ascencio, drew him and posted it on a Tumblr page. She then called on her peers to follow suit . "I think when you paint someone´s portrait, he´s no longer an unknown," she says. "He has a name, a face. He becomes a person." In a country where reprisals are common, she says getting so many people to sit down and draw was not easy. "Some people were afraid," she says, "but now we can go out and shout, and demand answers".

Image copyrightTumblrImage caption
Güerogüero's portrait

Another illustrator, known by the name Bef, is one of those that heeded the call. He chose to draw 21-year-old Bernardo Alcaraz - and above the image he wrote: "I, Bef, want to know what happened to Bernardo Flores Alcaraz". He told BBC Trending it is his "obligation" to get involved because "government-run media outlets are helping to hide the truth". He says social media protests are now the "only option" and each drawing is making a "powerful statement".

Güerogüero, another artist who got involved, says his "anger and sadness" meant, once he had learned of the campaign, he felt a "necessity" to get involved. He says people in his country are tired of the "violence, corruption and all the mud and dirt Mexico is buried in". He chose 19-year-old Carlos Lorenzo Hernandez Munoz as his muse, again demanding to "know what happened".

None of those involved have met the families of their subjects, but they say that is not necessary. Bef says he's helping his subject Bernardo's relatives by "making more people aware", while Güerogüero says that he wants Carlos' family to know that "thousands want justice".

Valeria's message is clear: "Benjamin Asencio is now a part of me and every student is now a part of every illustrator that's been working on this project." She says the best way to help is by doing what they have been doing for years: "drawing".

The Mexican government has ordered an inquiry into what happened. The governor of Guerrero, the state where the students disappeared, has resigned and the local mayor and local police chief are both on the run.

Reporting by Chris Hemmings

You can follow BBC Trending on Twitter @BBCtrending. All our stories are at bbc.com/trending